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Fixed the orienting ballistic path, though it doesn't properly handle

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arbitrarily oriented sprites. They currently have to "point" toward (1, 0,
0) as that is the direction that will be aligned with the velocity.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3619 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Michael Bayne
2005-06-23 03:49:18 +00:00
parent 732a6512c5
commit 2bf5936317
3 changed files with 64 additions and 38 deletions
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src/java/com/threerings/jme/sprite/BallisticPath.java
+3
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@@ -29,6 +29,9 @@ import com.jme.math.Vector3f;
*/
public class BallisticPath extends Path
{
/** Gravity: it's the law. */
public static final float G = -9.8f;
/**
* Moves the supplied sprite from the starting coordinate (which will
* be modified) using the starting velocity, under the specified
src/java/com/threerings/jme/sprite/OrientingBallisticPath.java
+23 -26
View File
@@ -21,8 +21,6 @@
package com.threerings.jme.sprite;
import com.jme.math.FastMath;
import com.jme.math.Matrix3f;
import com.jme.math.Quaternion;
import com.jme.math.Vector3f;
@@ -45,42 +43,41 @@ public class OrientingBallisticPath extends BallisticPath
{
super(sprite, start, velocity, accel, duration);
// rotate the sprite to start
rotate(orient, velocity);
// TODO: handle orient that is not (1, 0, 0)
_orient = orient;
// compute the up vector (opposite of acceleration)
_up = accel.negate();
_up.normalizeLocal();
computeRotation(velocity);
_sprite.getLocalRotation().set(_rotate);
}
// documentation inherited
public void update (float time)
{
// keep track of the old velocity before we update
_ovelocity.set(_velocity);
// do the normal update
super.update(time);
// rotate the sprite accordingly
rotate(_ovelocity, _velocity);
computeRotation(_velocity);
_sprite.getLocalRotation().set(_rotate);
}
protected void rotate (Vector3f oorient, Vector3f norient)
protected void computeRotation (Vector3f velocity)
{
// compute the cross product to get the normal to the plane
// defined by the velocity vectors
oorient.cross(norient, _normal);
// compute the angle between the two vectors
float angle = FastMath.acos(
oorient.dot(norient) / (norient.length() * oorient.length()));
// now use that to compute a rotation matrix from the old to the
// new vector
_rotate.fromAngleAxis(angle, _normal);
// finally rotate the sprite accordingly
_sprite.getLocalRotation().multLocal(_rotate);
_axes[0].set(velocity);
_axes[0].normalizeLocal();
_axes[0].cross(_up, _axes[1]);
_axes[1].normalizeLocal();
_axes[1].cross(_axes[0], _axes[2]);
_axes[2].cross(_axes[0], _axes[1]);
_rotate.fromAxes(_axes);
}
protected Vector3f _ovelocity = new Vector3f();
protected Vector3f _normal = new Vector3f();
protected Vector3f _orient;
protected Vector3f _up;
protected Vector3f[] _axes = {
new Vector3f(), new Vector3f(), new Vector3f() };
protected Quaternion _rotate = new Quaternion();
}
tests/src/java/com/threerings/jme/sprite/PathTest.java
+38 -12
View File
@@ -9,9 +9,12 @@ import com.jme.math.FastMath;
import com.jme.math.Matrix3f;
import com.jme.math.Quaternion;
import com.jme.math.Vector3f;
import com.jme.util.LoggingSystem;
import com.jme.renderer.ColorRGBA;
import com.jme.scene.shape.Box;
import com.jme.scene.shape.Quad;
import com.jme.scene.shape.Sphere;
import com.jme.scene.state.LightState;
import com.jme.util.LoggingSystem;
import com.threerings.jme.JmeApp;
@@ -24,25 +27,37 @@ public class PathTest extends JmeApp
{
super.initRoot();
float range = 56, muzvel = 24;
float dist = 10;
// set up the camera
Vector3f loc = new Vector3f(range/2, -range*2, 0);
Vector3f loc = new Vector3f(0, -dist, 10);
_camera.setLocation(loc);
Matrix3f rotm = new Matrix3f();
rotm.fromAngleAxis(-FastMath.PI/2, _camera.getLeft());
rotm.fromAngleAxis(-FastMath.PI/4, _camera.getLeft());
rotm.multLocal(_camera.getDirection());
rotm.multLocal(_camera.getUp());
rotm.multLocal(_camera.getLeft());
_camera.update();
Box box = new Box("box", new Vector3f(-1, -1, -1),
new Vector3f(1, 1, 1));
for (int yy = -1; yy < 1; yy++) {
for (int xx = -1; xx < 1; xx++) {
Quad quad = new Quad("ground", 10, 10);
quad.setLightCombineMode(LightState.OFF);
int index = (yy+1)*2 + (xx+1);
quad.setSolidColor(COLORS[index]);
quad.setLocalTranslation(
new Vector3f(xx * 10 + 5, yy * 10 + 5, -1));
_geom.attachChild(quad);
}
}
Box box = new Box("box", new Vector3f(-1, -0.5f, -0.25f),
new Vector3f(1, 0.5f, 0.25f));
_geom.attachChild(box);
Box box2 = new Box("box2", new Vector3f(-1, -1, -1),
new Vector3f(1, 1, 1));
box2.setLocalTranslation(new Vector3f(range, 0, 0));
Box box2 = new Box("box2", new Vector3f(-.1f, -.1f, -.1f),
new Vector3f(.1f, .1f, .1f));
box2.setLocalTranslation(new Vector3f(dist, dist, 0));
_geom.attachChild(box2);
Sprite shot = new Sprite();
@@ -52,15 +67,22 @@ public class PathTest extends JmeApp
Vector3f start = new Vector3f(0, 0, 0);
// start with the "cannon" pointed along the x axis
Vector3f vel = new Vector3f(1, 0, 0);
Vector3f diff = box2.getLocalTranslation().subtract(
box.getLocalTranslation());
Vector3f vel = diff.normalize();
float range = diff.length(), angle = -FastMath.PI/4;
Vector3f axis = UP.cross(vel);
axis.normalizeLocal();
// rotate it up (around the y axis) the necessary elevation
Quaternion rot = new Quaternion();
float angle = BallisticPath.computeElevation(range, muzvel, -9.8f);
rot.fromAngleAxis(angle, new Vector3f(0, 1, 0));
rot.fromAngleAxis(angle, axis);
rot.multLocal(vel);
// give the cannon its muzzle velocity
float muzvel = FastMath.sqrt(range * BallisticPath.G /
FastMath.sin(2*angle));
vel.multLocal(muzvel);
float time = BallisticPath.computeFlightTime(range, muzvel, angle);
@@ -69,6 +91,7 @@ public class PathTest extends JmeApp
System.out.println("Range: " + range);
System.out.println("Muzzle velocity: " + muzvel);
System.out.println("Rotation axis: " + axis);
System.out.println("Angle: " + angle + " (" +
(angle * 180 / FastMath.PI) + ")");
System.out.println("Flight time: " + time);
@@ -86,4 +109,7 @@ public class PathTest extends JmeApp
}
protected static final Vector3f GRAVITY = new Vector3f(0, 0, -9.8f);
protected static final Vector3f UP = new Vector3f(0, 0, 1);
protected static final ColorRGBA[] COLORS = {
ColorRGBA.red, ColorRGBA.green, ColorRGBA.blue, ColorRGBA.gray };
}